The LogCustomPropertyNodeID property contains the numeric ID of the logging information field for identification purposes. Each field has a corresponding flag in the LogExtFileFlags property which should be set if you want the information logged.
You can configure this property at the following locations in the IIS metabase.
IIS Admin Object Type
/LM/logging/Custom Logging/Extended Properties
/LM/logging/Custom Logging/Extended Properties/extended_property_name